An overview on the recent advancements of sustainable heterogeneous catalysts and prominent continuous reactor for biodiesel production

Biodiesel is a renewable energy source. However, high production cost, low product efficiency, and long reaction time have been the main technical challenges in biodiesel synthesis. Recently, various types of heterogeneous catalyst and continuous reactor have been invented for the production of biodiesel. But most of the catalysts are not suitable for large-scale industrial application for biodiesel synthesis due to high cost. Therefore, there is a need for exploring more suitable and economical heterogeneous catalyst. From literature, CaO derived catalyst from waste sources found to be the best heterogeneous catalyst for low-cost biodiesel synthesis. In continuous reactors, good mixing of reactants for mass transfer resistant is the primary requirement for good yield of biodiesel. Therefore, reverse flow helical coil reactor is found to be the good solution to overcome these problems which provide a good yield of biodiesel. Depending upon the type of catalysts and reactors used in this process, the reaction rate, energy consumption, molar ratio of methanol to oil and raw material will vary. Therefore, there is a need for a right combination of reactor and catalyst for getting higher biodiesel yield. (C) 2020 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.